The main objective of the study is to determine whether glatiramer acetate 20 mg once daily reduces the amount of axonal loss in the optic nerve after a first event of acute optic neuritis compared to placebo patients and to generate data supporting the potential neuroprotective effect of glatiramer acetate in a human in vivo model of axonal loss.

Inclusion Criteria:

• Age: 18 - 45 years

• Isolated, unilateral, first acute optic neuritis (AON) event consistent with inflammatory demyelinization, not explained by other etiologies. Onset of AON is defined by the presentation of visual disturbances.

• Able to provide written informed consent prior to enrollment

• Willing and able to comply with the protocol requirements for the duration of the study

• For women of child bearing potential:

  • A negative urine pregnancy test o
  • Willing to practice an acceptable method of birth control •

• Willing to receive a steroidal regimen

Exclusion Criteria:

• A diagnosis of clinically definite multiple sclerosis (MS) (Clinically Definite Multiple Sclerosis)
• Current use of any approved disease modifying agents for treatment of MS
• Prior clinical episode of optic neuritis in either eye
• Bilateral AON
• Inability to undergo study evaluations in both eyes
• Known ocular or neurological conditions or abnormalities other than refractive error that impair visual function
• Retrogeniculate visual loss
• Refractive error of greater than +6 or -6 diopters
• Neuromyelitis Optica (Devic's disease)
• Systemic diseases that cause inflammatory optic neuropathy, including but not limited to Sarcoidosis, Systemic lupus erythematosus (SLE), Wegener's Granulomatosis, Syphilis, human immunodeficiency virus (HIV)
• Known ocular conditions that preclude dilation
• Any condition that may interfere with performance of Optical Coherence Tomography (OCT): corneal, lens or fundoscopic abnormality, a co-morbid ocular condition not related to optic neuritis as detected on the OCT reading
• Any condition that precludes administration of Glatiramer Acetate, such as a known history of sensitivity to mannitol
• Diabetes Mellitus Types I or II
• Gastric bypass surgery
• Current use of chemotherapy or radiotherapy
• Treatments that may cause visual loss such as plaquenil, anti-tubercular agents, interferon (IFN)-alpha therapy, monoclonal antibodies Cardiac medications that may affect visual evaluations such as digitalis, amiodarone, quinine
• Ongoing treatment with steroids (for longer than 10 days) within the last 3 months
• Significant or unstable medical, systemic, psychiatric or logistical condition that affects the patient's ability to give informed consent or to complete the study procedures
• Use of an investigational drug within 30 days prior to randomization

Sponsor has the right 60 days before submission for publication to review/provide comments. If the Sponsor's review shows that potentially patentable subject matter would be disclosed, publication or public disclosure shall be delayed for up to 90 additional days in order for the Sponsor, or Sponsor's designees, to file the necessary patent applications. In multicenter trials, each PI will postpone single center publications until after disclosure or publication of multicenter data.